Washing apparatus for printing press cylinders having a spring-band freewheel tensioning device

Abstract

A washing apparatus for cleaning the surface of cylinders in a printing machine includes a fresh-cloth roller, a washing roller and a dirty-cloth roller. A washing cloth is transported from the fresh-cloth roller via the washing roller to the dirty-cloth roller. A spring-band freewheel in the form of a helical coil spring is wound non-positively on the shaft of the fresh-cloth roller. The spring-band freewheel free-wheels during the rotation of the shaft in the direction of tension applied to the washing cloth and blocks the shaft from rotating in the opposite direction. The necessary cloth tension is guaranteed, at the same time, by means of the resilient effect of the spring-band freewheel.

We claim as our invention: 
     
       1. In a washing apparatus employing a washing fluid and a washing cloth for washing a cylinder in a printing press wherein the washing apparatus includes a fresh-cloth supply roller, a dirty-cloth take-up roller and an intermediate washing roller with each of the rollers having a shaft journalled at its opposite ends in supporting frame parts, the washing cloth being drawn off the fresh-cloth supply roller and around the washing roller by tension resulting from winding the cloth onto the dirty-cloth take-up roller, and throw-on means for selectively causing the washing cylinder to press the washing cloth onto the surface of the cylinder, the improvement comprising a spring-band freewheel including a helical spring having a coil portion and first and second ends, said coil portion being disposed in close-fitting concentric relation on one end of said fresh-cloth supply roller shaft with said first spring end free and said second spring end projecting from said shaft substantially tangent to the direction of unwinding rotation thereof and fixed to one of said supporting frame parts whereby said coil portion of said spring-band freewheel loosens from said shaft during rotation of said shaft in the fresh-cloth supply direction and seizes onto said shaft incident to rotation of said shaft in the opposite direction. 
     
     
       2. A washing apparatus according to claim 1 wherein said coil portion of said spring-band freewheel has multiple coil turns wound concentrically around said shaft end. 
     
     
       3. A washing apparatus according to claim 2 wherein said coil portion of said spring-band freewheel is disposed concentrically about said shaft end between said clean cloth and said supporting frame part journalling said shaft end. 
     
     
       4. A washing apparatus according to claim 1 wherein said coil portion of said spring-band freewheel has at least one coil turn wound concentrically about said shaft end and said coil turn is circular in cross-section. 
     
     
       5. A washing apparatus according to claim 1 wherein said coil portion of said spring-band freewheel has at least one coil turn wound concentrically about said shaft end and said coil turn is rectangular in cross-section.